1. Field of the Invention
The present invention relates to touch responsive control of a computor organ or other keyboard electronic musical instrument.
2. Description of the Prior Art
In a conventional piano, both the maximum amplitude and harmonic content of each note will depend on the force and/or velocity with which the key is struck. In general, the harder the key is depressed, the greater will be both the maximum amplitude and the harmonic content. If a softer touch is used, the maximum amplitude will be less, and there will be fewer higher order harmonics present in the spectrum of the produced sound. A principal object of the present invention is to implement such touch response in an electronic musical instrument.
Although touch responsive transducers per se are known, another object of the present invention is to provide such a transducer having a digital output which is directly usable with a digital tone synthesizer. A further object is to facilitate the use of analog touch transducers in a digital musical instrument, by employing a single analog-to-digital converter that is shared by plural transducers.
The disclosed touch responsive system advantageously is used with the COMPUTOR ORGAN disclosed in the inventor's U.S. Pat. No. 3,809,786. In such instrument, the Fourier components of a musical sound are individually controlled in amplitude by harmonic coefficients C.sub.n associated with each harmonic order n. An object of the present invention is to implement touch responsive control of both amplitude and harmonic content in such a computor organ. However, the invention is not limited to use with the patented computor organ, but may be utilized with other electronic musical instruments in which the amplitude envelope is controlled by an amplitude scale factor. Thus the invention also may be used with a digital organ of the type disclosed in the inventor's U.S. Pat. No. 3,515,792 wherein musical tones are generated by repetitively accessing a waveshape stored in a memory.